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<h2><a name="SECTION0021410000000000000000"></a><a name="au-read-objects"></a>
<br>
19.4.1 AU_read Objects 
</h2>

<p>
AU_read objects, as returned by <tt class="function">open()</tt> above, have the
following methods:

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4578' xml:id='l2h-4578' class="method">close</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Close the stream, and make the instance unusable. (This is 
called automatically on deletion.)
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4579' xml:id='l2h-4579' class="method">getnchannels</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns number of audio channels (1 for mone, 2 for stereo).
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4580' xml:id='l2h-4580' class="method">getsampwidth</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns sample width in bytes.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4581' xml:id='l2h-4581' class="method">getframerate</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns sampling frequency.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4582' xml:id='l2h-4582' class="method">getnframes</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns number of audio frames.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4583' xml:id='l2h-4583' class="method">getcomptype</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns compression type.
Supported compression types are <code>'ULAW'</code>, <code>'ALAW'</code> and <code>'NONE'</code>.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4584' xml:id='l2h-4584' class="method">getcompname</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Human-readable version of <tt class="method">getcomptype()</tt>. 
The supported types have the respective names <code>'CCITT G.711
u-law'</code>, <code>'CCITT G.711 A-law'</code> and <code>'not compressed'</code>.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4585' xml:id='l2h-4585' class="method">getparams</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns a tuple <code>(<var>nchannels</var>, <var>sampwidth</var>,
<var>framerate</var>, <var>nframes</var>, <var>comptype</var>, <var>compname</var>)</code>,
equivalent to output of the <tt class="method">get*()</tt> methods.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4586' xml:id='l2h-4586' class="method">readframes</tt></b>(</nobr></td>
  <td><var>n</var>)</td></tr></table></dt>
<dd>
Reads and returns at most <var>n</var> frames of audio, as a string of
bytes.  The data will be returned in linear format.  If the original
data is in u-LAW format, it will be converted.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4587' xml:id='l2h-4587' class="method">rewind</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Rewind the file pointer to the beginning of the audio stream.
</dl>

<p>
The following two methods define a term ``position'' which is compatible
between them, and is otherwise implementation dependent.

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4588' xml:id='l2h-4588' class="method">setpos</tt></b>(</nobr></td>
  <td><var>pos</var>)</td></tr></table></dt>
<dd>
Set the file pointer to the specified position.  Only values returned
from <tt class="method">tell()</tt> should be used for <var>pos</var>.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4589' xml:id='l2h-4589' class="method">tell</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Return current file pointer position.  Note that the returned value
has nothing to do with the actual position in the file.
</dl>

<p>
The following two functions are defined for compatibility with the 
<tt class="module"><a href="module-aifc.html">aifc</a></tt>, and don't do anything interesting.

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4590' xml:id='l2h-4590' class="method">getmarkers</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Returns <code>None</code>.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-4591' xml:id='l2h-4591' class="method">getmark</tt></b>(</nobr></td>
  <td><var>id</var>)</td></tr></table></dt>
<dd>
Raise an error.
</dl>

<p>

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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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